1. Field of the Invention
The invention relates to surgical fasteners, endoscopic surgical instruments, and procedures. More particularly, the invention relates to surgical fasteners, endoscopic instruments, and procedures for the transoral plication and fastening together of portions of the stomach for the treatment of GERD.
2. State of the Art
Gastroesophageal reflux disease (GERD) or persistent heartburn is caused by an improper relaxation of the lower esophageal sphincter (LES) that allows the frequent regurgitation of acidic stomach contents into the esophagus. If left untreated, chronic reflux may cause esophageal stricture, bleeding ulcers, perforation, and scarring. Continued reflux may lead to Barrett's esophagus, which involves changes in the cells that make up the esophagus and may lead to cancer.
The current mode of treatment is primarily pharmacological starting with antacids and progressing to proton pump inhibitors (PPIs). The progression of the disease is noted by the development of a hiatal hernia caused by the stomach being forced into the thoracic cavity. The pharmacological treatment ends with double and triple dosing of PPIs. At the point that the patient is not responding to the PPIs, surgical intervention is often recommended.
The current standard for surgery is the Nissen fundoplication. The fundoplication procedure involves wrapping the fundus of the stomach around the lower end of the esophagus and fastening it in place to make the lower esophageal sphincter (LES) less compliable. Traditionally, this procedure is accomplished via open surgery with the use of sutures to secure the plicated fundus of the stomach around the esophagus without penetrating (incising) the stomach. However, with the advent of laparoscopic surgery came the development of a corresponding laparoscopic Nissen procedure.
In an effort to further reduce the invasiveness of treatment for GERD, endoscopic techniques are being explored. Techniques that are currently under trials include the implantation of bulking agents, cautery techniques to produce scarring, and suturing or otherwise fastening internal tissue.
For example, U.S. Pat. No. 5,403,326 to Harrison et al. discloses a method of performing endoscopic fundoplication using surgical staples or two-part surgical fasteners. The procedure disclosed by Harrison et al. involves performing two percutaneous endoscopic gastrotomies (incisions through the skin into the stomach) and the installation of two ports through which a stapler, an endoscope, and an esophageal manipulator (invagination device) are inserted. Under view of the endoscope, the esophageal manipulator is used to pull the interior of the esophagus into the stomach. When the esophagus is in position, with the fundus of the stomach plicated, the stapler is moved into position around the lower end of the esophagus and the plicated fundus is stapled to the esophagus. The process is repeated at different axial and rotary positions until the desired fundoplication is achieved. While, the procedure disclosed by Harrison et al. is a vast improvement over open surgery, it is still relatively invasive requiring two incisions through the stomach.
U.S. Pat. No. 5,571,116 to Bolanos et al. discloses a non-invasive treatment of gastroesophageal reflux disease which utilizes a remotely operable invagination device and a remotely operable surgical stapler, both of which are inserted transorally through the esophagus. According to the methods disclosed by Bolanos et al., the invagination device is inserted first and is used to clamp the gastroesophageal junction. The device is then moved distally, pulling the clamped gastroesophageal junction into the stomach, thereby invaginating the junction and involuting the surrounding fundic wall. The stapler is then inserted transorally and delivered to the invaginated junction where it is used to staple the fundic wall.
Bolanos et al. disclose several different invagination devices and several different staplers. Generally, each of the staplers disclosed by Bolanos et al. has an elongate body and a spring biased anvil which is rotatable approximately 15 degrees away from the body in order to locate the invaginated gastroesophageal junction between the body and the anvil. The body contains a staple cartridge holding a plurality of staples, and a staple firing knife. Each of the invagination devices disclosed by Bolanos et al. has a jaw member which is rotatable by at least 45 degrees and in some cases more than 90 degrees to an open position for grasping the gastroesophageal junction. One of the chief disadvantages of the methods and apparatus disclosed by Bolanos et al. is that the stapler and the invagination device are separately inserted but must both be present in the esophagus at the same time. With some of the embodiments disclosed, the presence of both instruments is significantly challenged by the size of the esophagus. Moreover, the esophagus cannot form a seal about both the instruments and, thus, it is difficult to insufflate the stomach to facilitate the procedure. In addition, the actuating mechanism of the device disclosed by Bolanos et al. is awkward. In particular, the stapler anvil is biased to the open position, and it is not clear whether or not the stapler anvil can be locked in a closed position without continuously holding down a lever. In addition, it appears that the staple firing trigger can be inadvertently operated before the anvil is in the closed position. This would result in inadvertent ejection of staples into the stomach or the esophagus of the patient.
U.S. Pat. No. 6,086,600 to Kortenbach discloses an endoscopic surgical instrument adapted to perform fundoplication, between the stomach wall and the esophagus. The instrument includes a flexible tube, a grasping and fastening end effector coupled to the distal end of the tube, and a manual actuator coupled to the proximal end of the tube. The manual actuator is coupled to the end effector by a plurality of flexible cables which extend through the tube. The tube contains a lumen for receiving a manipulable endoscope and the end effector includes a passage for the distal end of the endoscope. The end effector has a store for a plurality of male fastener parts, a store for a plurality of female fastener parts, a rotatable grasper, a rotatable fastener head for aligning a female fastener part and a male fastener part with tissues therebetween, and a firing member for pressing a male fastener part through tissues grasped by the grasper and into a female fastener part. According to a stated preferred embodiment, the overall diameters of the flexible tube and the end effector (when rotated to the open position) do not exceed approximately 20 mm so that the instrument may be delivered transorally to the fundus of the stomach.
While transoral fundoplication devices and methods hold promise, it is still difficult to deliver and manipulate the necessary apparatus transorally. One reason for the difficulty is that the overall diameter, or more accurately the cross sectional area, of the equipment is too large. Moreover, even if the Kortenbach device could be reduced to 20 mm in diameter (314 mm2 cross sectional area), it would still be difficult to manipulate. Those skilled in the art will appreciate that larger instruments are less pliable and the plication and fastening procedure requires that the instruments be retroflexed nearly 180 degrees. Moreover, it will be appreciated that large instruments obscure the endoscopic view of the surgical site.
Recently, PCT WO 00/78227 (NDO Surgical Inc.) has disclosed a device sized to receive an endoscope and which is purportedly capable of plicating and damaging portions of the stomach wall to effect serosa-to-serosa contact which results in stomach wall tissue adhesion. As a result, compliance of the tissue about the esophagus would be reduced and a flap (i.e., valve) would be formed about the LES. For this purpose, the plication and adhesion should preferably be created at the horseshoe-shaped tissue in the stomach surrounding the LES. The distance from the Z line (esophageal/stomach borderline) to the horseshoe-shaped target tissue is approximately 1 to 3 cm into the stomach and plication at this location permits the greatest stress to be placed on the tissue about the LES. In order to approach plication at this location the device has a particularly complicated and unwieldy multi-component end effector adapted to grab tissue, plicate the tissue, and fasten the tissue together. That is, while the above referenced device appears to offer a solution, it may not be practical to implement mechanically or operate during the procedure. Further, the above referenced device, while respectfully having a relatively smaller diameter than other prior art (approximately 18 mm in diameter and 254 mm2 in cross-sectional area) maintains that cross-sectional area over its entire length. In addition to limited flexibility, the size of the device renders it difficult to traverse the tracheopharangeal passage. Moreover, while it is desirable to plicate the stomach wall in a direction parallel to the esophagus in order to satisfactorily reduce compliance of the tissue, it is noted that the end effector of the above referenced device is unable to approach the target tissue from the desired direction.
It is also preferable that any fastener used for the apposition of tissue in the stomach cavity be removable in the event of tissue ischemia, vagus nerve irritation, or continued reflux, and be relatively non-injurious to the patient should the fastener inadvertently become loose from the device or dislodged from the tissue. In addition, current fasteners are difficult to locate within the stomach via an endoscope if it becomes necessary to find the fastener for removal.